This invention relates to compositions that exhibit both repellency and antistatic characteristics. This invention further relates to fibers, films, fabrics, coatings, and molded or blown articles comprising the compositions. In other aspects, this invention also relates to a topical treatment composition and to processes for imparting both repellency and antistatic characteristics to substrates.
Various fluorochemicals have been used to impart water and oil repellency, as well as soil resistance, to a variety of substrates (for example, textiles, carpet, leather, paper, and non-woven webs). These fluorochemicals have most often been applied topically (for example, by spraying, padding, or finish bath immersion), but some fluorochemicals have also been useful as polymer melt additives for preparing water- and oil-repellent polymeric fibers, films, fabrics, etc. The resulting repellent substrates have found use in numerous applications where water and/or oil repellency (as well as soil resistance) characteristics have been valued.
For some applications, however, antistatic properties have also been necessary or desirable.
Electrostatic charge buildup is responsible for a variety of problems in the processing and use of many industrial products and materials. Electrostatic charging can cause materials to stick together or to repel one another. This is a particular problem in fiber and textile processing. In addition, static charge buildup can cause objects to attract dirt and dust, thereby decreasing the effectiveness of fluorochemical repellents.
Sudden electrostatic discharges from insulating objects can also be a serious problem. With photographic film, such discharges can cause fogging and the appearance of artifacts. When flammable materials are present (for example, in a surgical environment), a static electric discharge can serve as an ignition source, resulting in fires and/or explosions. Static is a particular problem in the electronics industry, since modern electronic devices are extremely susceptible to permanent damage by static electric discharges.
However, conventional antistats (many of which are humectants that rely on the adsorption and conductivity of water for charge dissipation) have generally not been very effective in combination with fluorochemical repellents. The result of such combination has often been a substantial deterioration (or even elimination) of either antistatic or repellency characteristics (or both), relative to the use of either additive alone.
Furthermore, it has been particularly difficult to combine conventional antistats and fluorochemical repellents in polymer melt processing applications, as, for example, the water associated with humectant antistats vaporizes rapidly at melt processing temperatures. This has resulted in the undesirable formation of bubbles in the polymer and has caused screw slippage in extrusion equipment. Many antistats have also lacked the requisite thermal stability, leading to the production of objectionable odors (for example, in melt blowing applications, where high extrusion temperatures are involved).
Thus, there remains a need in the art for antistatic agents and repellents that can be effectively combined to impart both good antistatic characteristics and good repellency characteristics to substrates and that, in particular, can be utilized as melt additives without causing processing problems or melt defects.
Briefly, in one aspect, this invention provides a water- and oil-repellent, antistatic composition comprising (a) at least one nonpolymeric ionic salt consisting of (i) at least one monovalent metal cation, divalent metal cation, or organic onium cation (for example, a quaternary ammonium ion) and (ii) at least one weakly coordinating anion, the conjugate acid of the anion having an acidity greater than or equal to that of a hydrocarbon sulfonic acid (for example, a bis(perfluoroalkanesulfonyl)imide ion), and with the proviso that the anion is organic or fluoroorganic when the cation is a metal; (b) at least one fluorochemical repellency-imparting additive or repellent; and (c) at least one insulating material. As used herein, the term xe2x80x9corganic onium cationxe2x80x9d means a positively charged organic ion having at least part of its charge localized on at least one heteroatom (for example, nitrogen, phosphorus, sulfur, iodine, or oxygen). Preferably, the insulating material is a thermoplastic or thermosetting polymer (more preferably, thermoplastic), and the composition is prepared by forming a blend (more preferably, a melt blend) of the components.
It has been discovered that the above-described class of ionic salt antistatic agents or antistats can be effectively combined with fluorochemical repellents to impart both good antistatic characteristics and good repellency characteristics to a variety of insulating materials. The antistats and repellents can be combined not only in topical treatments (external additives) but even (and preferably) as melt additives (internal additives) without causing processing problems or melt defects. The antistat/repellent combination used in the composition of the invention is surprisingly effective at dissipating the static charge that can accumulate in an otherwise insulating substrate such as a polymer film or fabric, while also imparting durable water and oil repellency (and soil resistance). Even more suprisingly, when used in topical treatments or as polymer melt additives in polypropylene melt-blown nonwoven fabric, certain preferred antistats exhibit synergistic behavior when combined with the repellent(s), in that better static dissipation rates are obtained than when the antistats are used alone.
The combination of ionic salt antistat(s) and fluorochemical repellent(s) used in the composition of the invention is compatible with a variety of polymers. Since many of the antistats are hydrophobic (immiscible with water), the antistatic performance of the combination is often relatively independent of atmospheric humidity levels and durable even under exposure to aqueous environments. In addition, since many of the antistats are stable at temperatures up to 300-500xc2x0 C., the combination of such antistat(s) with thermally stable fluorochemical repellent(s) is particularly well-suited for use in high temperature polymer melt additive applications and in applications where the use temperatures are very high.
The combination of ionic salt antistat(s) and fluorochemical repellent(s) used in the composition of the invention therefore meets the need in the art for antistatic agents and repellents that can be effectively combined to impart both good antistatic characteristics and good repellency characteristics to substrates and that, in particular, can be utilized as melt additives without causing processing problems or melt defects.
In other aspects, this invention also provides fiber, fabric, film, a coating, and a molded or blown article comprising the composition of the invention; processes for imparting both repellency and antistatic characteristics to a substrate, for example, by bulk addition or by topical treatment; and a topical treatment composition comprising (a) at least one nonpolymeric ionic salt consisting of (i) at least one monovalent metal cation, divalent metal cation, or organic onium cation and (ii) at least one weakly coordinating anion, the conjugate acid of the anion having an acidity greater than or equal to that of a hydrocarbon sulfonic acid, and with the proviso that the anion is organic or fluoroorganic when the cation is a metal, and (b) at least one fluorochemical repellency-imparting additive or repellent.
Antistats
Ionic salts suitable for use as antistats in the composition of the invention are those that consist of a monovalent or divalent metal cation (preferably, monovalent) or an organic onium cation (preferably, an organic onium cation) and a weakly coordinating anion. Suitable metal cations include, for example, lithium, calcium, sodium, potassium, magnesium, zinc, iron, nickel, and copper, with sodium and lithium being preferred. The organic onium cation can comprise a heteroatom (for example, nitrogen, phosphorus, sulfur, iodine, or oxygen; preferably, nitrogen or phosphorus; more preferably, nitrogen) as the charge center or as a component element in a charge-delocalized chain or ring structure. The organic onium cation can be cyclic (that is, where the charge center(s) of the cation are ring atoms) or acyclic (that is, where the charge center(s) of the cation are not ring atoms but can have cyclic substituents). The cyclic cations can be aromatic, unsaturated but nonaromatic, or saturated, and the acyclic cations can be saturated or unsaturated.
The cyclic cations can contain one or more ring heteroatoms (for example, nitrogen, oxygen, or sulfur), and the ring atoms can bear substituents (for example, hydrogen, halogen, or organic groups such as alkyl, alicyclic, aryl, alkalicyclic, alkaryl, alicyclicalkyl, aralkyl, aralicyclic, and alicyclicaryl groups). Separate alkyl substituents can be joined together to constitute a unitary alkylene radical of from 2 to 4 carbon atoms forming a ring structure. Organic substituents can contain one or more heteroatoms such as, for example, nitrogen, oxygen, sulfur, phosphorus, or halogen (and thus can be fluoroorganic in nature).
The acyclic cations can have at least one (preferably, at least two; more preferably, at least three; most preferably, four) charge center-bonded organic substituents or R groups, with the remaining substituents being hydrogen. The R groups can be cyclic or acyclic, saturated or unsaturated, aromatic or nonaromatic, and can contain one or more heteroatoms such as, for example, nitrogen, oxygen, sulfur, phosphorus, or halogen (and thus can be fluoroorganic in nature).
Preferably, the organic onium cation is acyclic or unsaturated cyclic. More preferably, it is acyclic or aromatic, most preferably, acyclic.
Preferred acyclic organic onium cations are nitrogen onium (ammonium) and phosphorus onium (phosphonium) cations that are quaternary or tertiary (most preferably, quaternary) cations. The quaternary and tertiary cations are preferably of low symmetry (having at least two, preferably at least three, different charge center-bonded organic substituents or R groups as defined above) and more preferably contain at least one hydroxyl group in at least one charge center-bonded organic substituent. Most preferred acyclic organic onium cations are the nitrogen onium cations described below for the ionic salt antistats of Formula I.
Preferred aromatic organic onium cations are the nitrogen onium cations selected from the group consisting of 
wherein R1, R2, R3, R4, R5, and R6 are independently selected from the group consisting of H, F, alkyl groups of from 1 to about 18 carbon atoms (preferably, from 1 to about 11 carbon atoms), two said alkyl groups joined together to form a unitary alkylene radical of from 2 to 4 carbon atoms forming a ring structure, and phenyl groups; and wherein said alkyl groups, alkylene radicals, or phenyl groups can comprise one or more substituent groups (preferably, a group that is capable of hydrogen bonding, for example, an amino, hydroxyl, acetyl, or acetamide group, or an electron-withdrawing group, for example, Fxe2x80x94, Clxe2x80x94, CF3xe2x80x94, SF5xe2x80x94, CF3Sxe2x80x94, (CF3)2CHSxe2x80x94, and (CF3)3 CSxe2x80x94).
Preferred unsaturated cyclic, nonaromatic organic onium cations include the nitrogen onium cations represented by the following formula 
where R1, R2, R3, R4, R5, R6, and R7 are defined as R1, R2, R3, R4, R5, and R6 are defined above for the preferred aromatic organic onium cations.
Suitable weakly coordinating anions have a conjugate acid that is at least as acidic as a hydrocarbon sulfonic acid (preferably, a hydrocarbon sulfonic acid having from 1 to about 20 carbon atoms; more preferably, an alkane, aryl, or alkaryl sulfonic acid having from 1 to about 8 carbon atoms; even more preferably, methane or p-toluene sulfonic acid; most preferably, p-toluene sulfonic acid). Preferably, the conjugate acid is a strong acid. More preferably, the Hammett acidity function, H0, of the neat conjugate acid of the anion is less than about xe2x88x927 (most preferably, less than about xe2x88x9210).
Representative examples of suitable weakly coordinating anions include BF4xe2x80x94; PF6xe2x80x94; SbF6xe2x80x94; AsF6xe2x80x94; ClO4xe2x80x94; NO3xe2x80x94; Clxe2x80x94; Brxe2x80x94; Fxe2x80x94; HSO4xe2x80x94; H2PO4xe2x80x94; organic anions such as alkane, aryl, and alkaryl sulfonates; fluorinated and unfluorinated tetraarylborates; carboranes and halogen-, alkyl-, or haloakyl-substituted carborane anions including metallocarborane anions; teflates (for example, xe2x88x92OTeF5, xe2x88x92B(OTeF5)4, and xe2x88x92Pd(OTeF5)4); and fluoroorganic anions such as perfluoroalkanesulfonates, cyanoperfluoroalkanesulfonylamides, bis(cyano)perfluoroalkanesulfonylmethides, bis(perfluoroalkanesulfonyl)imides, bis(perfluoroalkanesulfonyl)methides, and tris(perfluoroalkanesulfonyl)methides; and the like. Preferred anions include organic and fluoroorganic anions (more preferably, alkane, aryl, and alkaryl sulfonates, as well as perfluoroalkanesulfonates, bis(perfluoroalkanesulfonyl)imides, and tris(perfluoroalkanesulfonyl)methides; most preferably, alkane sulfonates, perfluoroalkanesulfonates, and bis(perfluoroalkanesulfonyl)imides).
The fluoroorganic anions can be either fully fluorinated, that is perfluorinated, or partially fluorinated (within the organic portion thereof). Preferred fluoroorganic anions include those that comprise at least one highly fluorinated alkanesulfonyl group, that is, a perfluoroalkanesulfonyl group or a partially fluorinated alkanesulfonyl group wherein all non-fluorine carbon-bonded substituents are bonded to carbon atoms other than the carbon atom that is directly bonded to the sulfonyl group (preferably, all non-fluorine carbon-bonded substituents are bonded to carbon atoms that are more than two carbon atoms away from the sulfonyl group).
Preferably, the fluoroorganic anion is at least about 80 percent fluorinated (that is, at least about 80 percent of the carbon-bonded substituents of the anion are fluorine atoms). More preferably, the anion is perfluorinated (that is, fully fluorinated, where all of the carbon-bonded substituents are fluorine atoms). The anions, including the preferred perfluorinated anions, can contain one or more. catenary (that is, in-chain) heteroatoms such as, for example, nitrogen, oxygen, or sulfur.
Preferred fluoroorganic anions include perfluoroalkanesulfonates, bis(perfluoroalkanesulfonyl)imides, and tris(perfluoroalkanesulfonyl)methides. The perfluoroalkanesulfonates and bis(perfluoroalkanesulfonyl)imides are more preferred anions, with the perfluoroalkanesulfonates being most preferred.
The ionic salt antistats can be solids or liquids under use conditions but preferably have melting points less than about 150xc2x0 C. (more preferably, less than about 50xc2x0 C.; most preferably, less than about 25xc2x0 C.). Liquid ionic salts are preferred due to their generally better static dissipative performance. For use as polymer melt additives, the ionic salt antistats are preferably stable at temperatures of about 250xc2x0 C. and above (more preferably, about 300xc2x0 C. and above) and are preferably miscible with the insulating material at the melt processing temperature. (In other words, the onset of decomposition of the antistats is above such temperatures.) Preferred ionic salt antistats for polymer melt additive applications include those having cations selected from the group consisting of alkyl phosphonium cations, aromatic nitrogen onium cations (preferably, the preferred aromatic organic onium cations set forth above), and acyclic nitrogen onium cations (preferably, the cations shown in Formula I below); and having organic or fluoroorganic anions (preferably, anions selected from the group consisting of alkane sulfonates, aryl sulfonates, alkaryl sulfonates, perfluoroalkanesulfonates, bis(perfluoroalkanesulfonyl)imides, and tris(perfluoroalkanesulfonyl)methides; more preferably, alkane sulfonates, perfluoroalkanesulfonates, and bis(perfluoroalkanesulfonyl)imides); most preferably, perfluoroalkanesulfonates and bis(perfluoroalkanesulfonyl)imides.
The antistats are also preferably hydrophobic. Thus, a preferred class of ionic salt antistats for use in the composition of the invention includes those that consist of (a) an aromatic nitrogen onium cation selected from the group consisting of 
wherein R1, R2, R3, R4, R5, and R6 are independently selected from the group consisting of H, F, alkyl groups of from 1 to about 18 carbon atoms (preferably, from 1 to about 11 carbon atoms), two said alkyl groups joined together to form a unitary alkylene radical of from 2 to 4 carbon atoms forming a ring structure, and phenyl groups; and wherein said alkyl groups, alkylene radicals, or phenyl groups can comprise one or more substituent groups (preferably, an electron-withdrawing group, for example, Fxe2x80x94, Clxe2x80x94, CF3xe2x80x94, SF5xe2x80x94, CF3Sxe2x80x94, (CF3)2CHSxe2x80x94, and (CF3)3 CSxe2x80x94); and (b) a weakly coordinating fluoroorganic anion in accordance with the above description or a weakly coordinating anion selected from the group consisting of BF4xe2x80x94, PF6xe2x80x94, AsF6xe2x80x94, and SbF6xe2x80x94. This preferred class comprises a most preferred subclass of the hydrophobic ionic liquids described in U.S. Pat. No. 5,827,602 (Koch et al.), the description of the members of which is incorporated herein by reference.
Another preferred class of ionic salt antistats useful in preparing the composition of the invention is the class of compounds represented by Formula I below
(R1)4-zN+[(CH2)qOR2]z Xxe2x88x92xe2x80x83xe2x80x83(I)
wherein each R1 is independently selected from the group consisting of alkyl, alicyclic, aryl, alkalicyclic, alkaryl, alicyclicalkyl, aralkyl, aralicyclic, and alicyclicaryl moieties that can contain one or more heteroatoms such as, for example, nitrogen, oxygen, sulfur, phosphorus, or halogen (and thus can be fluoroorganic in nature); each R2 is independently selected from the group consisting of hydrogen and the moieties described above for R1; z is an integer of 1 to 4; q is an integer of 1 to 4; and Xxe2x88x92 is a weakly coordinating alkane sulfonate, aryl sulfonate, alkaryl sulfonate, or fluoroorganic anion as described above (preferably, a fluoroorganic anion). R1 is preferably alkyl, and R2 is preferably selected from the group consisting of hydrogen, alkyl, and acyl (more preferably, hydrogen or acyl; most preferably, hydrogen). Most preferably, z is 1, q is 2, R1 is alkyl, and R2 is hydrogen.
Many of the above-described ionic salt antistats (for example, metal bis(perfluoroalkanesulfonyl)imides, metal perfluoroalkanesulfonates, onium halides, onium alkanesulfonates, onium arylsulfonates, onium tetrafluoroborates, and onium hexafluorophosphates) are commercially available and can also be prepared by standard methods known in the art. Other ionic salt antistats comprising an organic onium cation can be prepared by ion exchange or metathesis reactions, which are also well known in the art. For example, a precursor onium salt can be combined with a precursor metal salt or the corresponding acid of a weakly coordinating anion in aqueous solution. Upon combining, the desired product (the onium salt of the weakly coordinating anion) precipitates (as a liquid or solid) or can be preferentially extracted into an organic solvent (for example, methylene chloride). The product can be isolated by filtration or by liquid/liquid phase separation, can be washed with water to completely remove byproduct metal salt or acid (if present), and can then be dried thoroughly under vacuum to remove all volatiles (including water and organic solvent, if present). Similar metathesis reactions can be conducted in organic solvents (for example, acetonitrile) rather than in water, and, in this case, the salt byproduct generally preferentially precipitates, while the desired product salt remains dissolved in the organic solvent (from which it can be isolated using standard experimental techniques).
Weakly coordinating fluoroorganic anions (for use in preparing such ionic salts) can be prepared by standard methods known in the art, and metal salts of many are commercially available. Such methods include the anion precursor preparative methods described in the following references, the descriptions of which are incorporated herein by reference: imide precursorsxe2x80x94U.S. Pat. Nos. 5,874,616 (Howells et al.), U.S. Pat. No. 5,723,664 (Sakaguchi et al.), U.S. Pat. No. 5,072,040 (Armand), and U.S. Pat. No. 4,387,222 (Koshar); methide precursorsxe2x80x94U.S. Pat. No. 5,554,664 (Lamanna et al.) and U.S. Pat. No. 5,273,840 (Dominey); sulfonate precursorsxe2x80x94U.S. Pat. No. 5,176,943 (Wou), U.S. Pat. No. 4,582,781 (Chen et al.), U.S. Pat. No. 3,476,753 (Hanson), and U.S. Pat. No. 2,732,398 (Brice et al.); sulfonate, imide, and methide precursors having caternary oxygen or nitrogen in a fluorochemical groupxe2x80x94U.S. Pat. No. 5,514,493 (Waddell et al.); disulfone precursorsxe2x80x94R. J. Koshar and R. A. Mitsch, J. Org. Chem., 38, 3358 (1973) and U.S. Pat. No. 5,136,097 (Armand).
In general, cyano-containing methides and amides containing fluoroalkanesulfonyl groups can be prepared by the reaction of fluoroalkanesulfonyl fluorides, RfSO2F, with anhydrous malononitrile or cyanamide, respectively, in the presence of a non-nucleophilic base. This synthetic procedure is described in Scheme 1 of U.S. Pat. No. 5,874,616 (Howells et al.) for the preparation of bis(fluoroalkanesulfonyl)imides (the description of which is incorporated herein by reference) and involves the substitution of either malononitrile or cyanamide for the fluoroalkanesulfonamide. The resulting intermediate non-nucleophilic base cation-containing methide or amide salt can be converted to the desired cation salt (typically lithium) via standard metathesis reactions well known in the art.
Representative examples of useful ionic salt antistats include octyldimethyl-2-hydroxyethylammonium bis(trifluoromethylsulfonyl)imide: [C8H17N+(CH3)2CH2CH2OH xe2x88x92N(SO2CF3)2], octyldimethyl-2-hydroxyethylammonium perfluorobutanesulfonate: [C8H17H+(CH3)2CH2CH2OH xe2x88x92OSO2C4F9], octyldimethyl-2-hydroxyethylammonium trifluoromethanesulfonate: [C8H17H+(CH3)2CH2CH2OH xe2x88x92OSO2CF3], octyldimethyl-2-hydroxyethylammonium tris(trifluoromethanesulfonyl)methide: [C8H17N+(CH3)2CH2CH2OH xe2x88x92C(SO2CF3)3], trimethyl-2-acetoxyethylammonium bis(trifluoromethylsulfonyl)imide: [(CH3)3N+CH2CH2OC(O)CH3 xe2x88x92N(SO2CF3)2], trimethyl-2-hydroxyethylammonium bis(perfluorobutanesulfonyl)imide: [(CH3)3N+CH2CH2OH xe2x88x92N(SO2C4F9)2], triethylammonium bis(perfluoroethanesulfonyl)imide: [Et3N+H xe2x88x92N(SO2C2F5)2], tetraethylammonium trifluoromethanesulfonate: [CF3SO3xe2x88x92+NEt4], tetraethylammonium bis(trifluoromethanesulfonyl)imide: [(CF3SO2)2Nxe2x88x92+NEt4], tetramethylammonium tris(trifluoromethanesulfonyl)methide: [(CH3)4N+xe2x88x92C(SO2CF3)3], tetrabutylammonium bis(trifluoromethanesulfonyl)imide: [(C4H9)4N+xe2x88x92N(SO2CF3)2], trimethyl-3-perfluorooctylsulfonamidopropylammonium bis(trifluoromethanesulfonyl)imide: [C8F17SO2NH(CH2)3N+(CH3)3 xe2x88x92N(SO2CF3)2], 1-hexadecylpyridinium bis(perfluoroethanesulfonyl)imide: [n-C16H33-cyc-N+C5H5 xe2x88x92N(SO2C2F5)2], 1-hexadecylpyridinium perfluorobutanesulfonate: [n-C16H33-cyc-N+C5H5 xe2x88x92OSO2C4F9], 1-hexadecylpyridinium perfluorooctanesulfonate: [n-C16H33-cyc-N+C5H5 xe2x88x92OSO2C8F17], n-butylpyridinium bis(trifluoromethanesulfonyl)imide: [n-C4H9-cyc-N+C5H5 xe2x88x92N(SO2CF3)2], n-butylpyridinium perfluorobutanesulfonate: [n-C4H9-cyc-N+C5H5 xe2x88x92OSO2C4F9], 1,3-ethylmethylimidazolium bis(trifluoromethanesulfonyl)imide: [CH3-cyc-(N+C2H2NCH)CH2CH3 xe2x88x92N(SO2CF3)2], 1,3-ethylmethylimidazolium nonafluorobutanesulfonate: [CH3-cyc-(N+C2H2NCH)CH2CH3 xe2x88x92OSO2C4F9], 1,3-ethylmethylimidazolium trifluoromethanesulfonate: [CH3-cyc-(N+C2H2NCH)CH2CH3 xe2x88x92OSO2CF3], 1,3-ethylmethylimidazolium hexafluorophosphate: [CH3-cyc-(N+C2H2NCH)CH2CH3 PF6xe2x88x92], 1,3-ethylmethylimidazolium tetrafluoroborate: [CH3-cyc-(N+C2H2NCH)CH2CH3 BF4xe2x88x92], lithium perfluorobutanesulfonate: [Li+xe2x88x92OSO2C4F9], lithium trifluoromethanesulfonate: [Li+xe2x88x92OSO2CF3], lithium bis(trifluoromethanesulfonyl)imide: [Li+xe2x88x92N(SO2CF3)2], lithium tris(trifluoromethanesulfonyl)methide: [Li+xe2x88x92C(SO2CF3)3], sodium phenylbis(trifluoromethanesulfonyl)methide: [Na+xe2x88x92C(C6H5)(SO2CF3)2], octyldimethyl-2-hydroxyethylammonium teflate: [C8H17N+(CH3)2CH2CH2OH xe2x88x92OTeF5], lithium permethylmonocarba-closo-dodecaborate: [Li+xe2x88x92CB11(CH3)12], sodium monocarba-closo-dodecaborate: [Na+xe2x88x92CB11H12], sodium tetrakis-(pentafluorophenyl)borate: [Na+xe2x88x92B(C6F5)4], octyldimethyl-2-hydroxyethylammonium methanesulfonate: [C8H17N+(CH3)2CH2CH2OH xe2x88x92OSO2CH3], tetrabutylphosphonium perfluorobutanesulfonate: [(C4H9)4P+xe2x88x92OSO2C4F9], tetraphenylphosphonium bis(trifluoromethanesulfonyl)imide: [(C6H5)4P+xe2x88x92N(SO2CF3)2], trioctylmethylammonium chloride: [(C8H17)3(CH3)N+ Clxe2x88x92], trioctylmethylammonium trifluoromethanesulfonate: [(C8H17)3(CH3)N+xe2x88x92OSO2CF3], trioctylmethylammonium perfluorobutanesulfonate: [(C8H17)3(CH3)N+xe2x88x92OSO2C4F9], 3-(2-hydroxyethyl)-1-methyl-2-undecylimidazolinium p-toluenesulfonate: [CH3-cyc-(N+C2H4N(CH2CH2OH)C)C11H23 xe2x88x92OSO2C6H4CH3], 1-dodecyl-2-ethyl-3-(2-hydroxyethyl)imidazolinium p-toluenesulfonate: [C12H25-cyc-(N+C2H4N(CH2CH2OH)C)C2H5 xe2x88x92OSO2C6H4CH3], 1,2-dimethyl-3-propylimidazolium bis(trifluoromethanesulfonyl)imide, 1,2-dimethyl-3-propylimidazolium tris(trifluoromethanesulfonyl)methide, 1,2-dimethyl-3-propylimidazolium trifluoromethanesulfonyl perfluorobutanesulfonylimide, 1-ethyl-3-methylimidazolium cyanotrifluoromethanesulfonylamide, 1-ethyl-3-methylimidazolium bis(cyano)trifluoromethanesulfonylmethide, 1-ethyl-3-methylimidazolium trifluoromethanesulfonylperfluorobutanesulfonylimide, octyldimethyl-2-hydroxyethylammonium trifluoromethylsulfonylperfluorobutanesulfonylimide, 2-hydroxyethyltrimethylammonium trifluoromethylsulfonylperfluorobutanesulfonylimide, 2-methoxyethyltrimethylammonium bis(trifluoromethanesulfonyl)imide octyldimethyl-2-hydroxyethylammonium bis(cyano)trifluoromethanesulfonylmethide, trimethyl-2-acetoxyethylammonium trifluoromethylsulfonylperfluorobutanesulfonylimide, 1-butylpyridinium trifluoromethylsulfonylperfluorobutanesulfonylimide, 2-ethoxyethyltrimethylammonium trifluoromethanesulfonate, 1-butyl-3-methylimidazolium perfluorobutanesulfonate, perfluoro-1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1-ethyl-2-methylpyrazolium perfluorobutanesulfonate, 1-butyl-2-ethylpyrazolium trifluoromethanesulfonate, N-ethylthiazolium bis(trifluoromethanesulfonyl)imide, N-ethyloxazolium bis(trifluoromethanesulfonyl)imide, and 1-butylpyrimidinium perfluorobutanesulfonylbis(trifluoromethanesulfonyl)-methide, 1,3-ethylmethylimidazolium hexafluorophosphate, 1,3-ethylmethylimidazolium tetrafluoroborate, and mixtures thereof.
Preferred ionic salt antistats include octyldimethyl-2-hydroxyethylammonium bis(trifluoromethylsulfonyl)imide: [C8H17N+(CH3)2CH2CH2OH xe2x88x92N(SO2CF3)2], octyldimethyl-2-hydroxyethylammonium perfluorobutanesulfonate: [C8H17N+(CH3)2Ch2Ch2OH xe2x88x92OSO2C4F9], octyldimethyl-2-hydroxyethylammonium trifluoromethanesulfonate: [C8H17N+(CH3)2CH2Ch2OH xe2x88x92OSO2CF3], octyldimethyl-2-hydroxyethylammonium tris(trifluoromethanesulfonyl)methide: [C8H17N+(CH3)2CH2CH2OH xe2x88x92C(SO2CF3)3], trimethyl-2-acetoxyethylammonium bis(trifluoromethylsulfonyl)imide: [(CH3)3N+CH2CH2OC(O)CH3 xe2x88x92N(SO2CF3)2], trimethyl-2-hydroxyethylammonium bis(perfluorobutanesulfonyl)imide: [(CH3)3N+CH2CH2OH xe2x88x92N(SO2C4F9)2], triethylammonium bis(perfluoroethanesulfonyl)imide: [Et3N+H xe2x88x92N(SO2C2F5)2], tetraethylammonium trifluoromethanesulfonate: [CF3SO3xe2x88x92+NEt4], tetraethylammonium bis(trifluoromethanesulfonyl)imide: [(CF3SO2)2Nxe2x88x92+NEt4], tetramethylammonium tris(trifluoromethanesulfonyl)methide: [(CH3)4N+xe2x88x92C(SO2CF3)3], tetrabutylammonium bis(trifluoromethanesulfonyl)imide: [(C4H9)4N+xe2x88x92N(SO2CF3)2], trimethyl-3-perfluorooctylsulfonamidopropylammonium bis(trifluoromethanesulfonyl)imide: [C8F17SO2NH(CH2)3N+(CH3)3 xe2x88x92N(SO2CF3)2], 1-hexadecylpyridinium bis(perfluoroethanesulfonyl)imide: [n-C16H33-cyc-N+C5H5 xe2x88x92N(SO2C2F5)2], 1-hexadecylpyridinium perfluorobutanesulfonate: [n-C16H33-cyc-N+C5H5 xe2x88x92OSO2C4F9], 1-hexadecylpyridinium perfluorooctanesulfonate: [n-C16H33-cyc-N+C5H5 xe2x88x92OSO2C8F17], n-butylpyridinium bis(trifluoromethanesulfonyl)imide: [n-C4H9-cyc-N+C5H5 xe2x88x92N(SO2CF3)2], n-butylpyridinium perfluorobutanesulfonate: [n-C4H9-cyc-N+C5H5 xe2x88x92OSO2C4F9], 1,3-ethylmethylimidazolium bis(trifluoromethanesulfonyl)imide: [CH3-cyc-(N+C2H2NCH)CH2CH3 xe2x88x92N(SO2CF3)2], 1,3-ethylmethylimidazolium nonafluorobutanesulfonate: [CH3-cyc-(N+C2H2NCH)CH2CH3 xe2x88x92OSO2C4F9], 1,3-ethylmethylimidazolium trifluoromethanesulfonate: [CH3-cyc-(N+C2H2NCH)CH2CH3 xe2x88x92OSO2CF3], lithium perfluorobutanesulfonate: [Li+xe2x88x92OSO2C4F9], lithium trifluoromethanesulfonate: [Li+xe2x88x92OSO2CF3], lithium bis(trifluoromethanesulfonyl)imide: [Li+xe2x88x92N(SO2CF3)2], tetrabutylphosphonium perfluorobutanesulfonate: [(C4H9)4P+xe2x88x92OSO2C4F9], octyldimethyl-2-hydroxyethylammonium methanesulfonate: [C8H17N+(CH3)2CH2CH2OH xe2x88x92OSO2CH3], 1-dodecyl-2-ethyl-3-(2-hydroxyethyl)imidazolinium p-toluenesulfonate: [C12H25-cyc-(N+C2H4N(CH2CH2OH)C)C2H5 xe2x88x92OSO2C6H4CH3], 1,3-ethylmethylimidazolium tetrafluoroborate, and mixtures thereof.
More preferred ionic salt antistats include octyldimethyl-2-hydroxyethylammonium bis(trifluoromethylsulfonyl)imide, octyldimethyl-2-hydroxyethylammonium perfluorobutanesulfonate, octyldimethyl-2-hydroxyethylammonium trifluoromethanesulfonate, triethylammonium bis(perfluoroethanesulfonyl)imide, tetraethylammonium trifluoromethanesulfonate, trimethyl-3-perfluorooctylsulfonamidopropylammonium bis(trifluoromethanesulfonyl)imide, 1,3-ethylmethylimidazolium nonafluorobutanesulfonate, 1,3-ethylmethylimidazolium bis(trifluoromethanesulfonyl)imide, 1,3-ethylmethylimidazolium trifluoromethanesulfonate, tetrabutylphosphonium perfluorobutanesulfonate, and mixtures thereof.
Most preferred ionic salt antistats include octyldimethyl-2-hydroxyethylammonium bis (trifluoromethylsulfonyl)imide, octyldimethyl-2-hydroxyethylammonium trifluoromethanesulfonate, octyldimethyl-2-hydroxyethylammonium nonafluorobutanesulfonate, triethylammonium bis(perfluoroethanesulfonyl)imide, 1,3-ethylmethylimidazolium nonafluorobutanesulfonate, 1,3-ethylmethylimidazolium bis(trifluoromethanesulfonyl)imide, 1,3-ethylmethylimidazolium trifluoromethanesulfonate, tetrabutylphosphonium perfluorobutanesulfonate, and mixtures thereof, with further preferences being in accordance with the general cation and anion preferences set forth above.
Fluorochemical Repellents
Suitable fluorochemical repellency-imparting additives or repellents for use in the composition of the invention are those that comprise at least one fluorochemical group, preferably, at least one fluoroaliphatic or fluoroalicyclic group. Such fluorochemicals include any of the fluorochemical group-containing polymeric and oligomeric compounds known in the art to impart water and oil repellency to substrates. These polymeric and oligomeric fluorochemicals typically comprise one or more fluorochemical groups that contain a perfluorinated carbon chain having from 3 to about 20 carbon atoms, more preferably from about 4 to about 12 carbon atoms. These fluorochemical groups can contain straight chain, branched chain, or cyclic fluorinated alkylene groups or any combination thereof. The fluorochemical groups can optionally contain catenary (i.e., in-chain) heteroatoms such as oxygen, divalent or hexavalent sulfur, or nitrogen. Fully-fluorinated groups are preferred, but hydrogen or chlorine atoms can also be present as substituents, provided that no more than one atom of either is present for every two carbon atoms. It is additionally preferred that any fluorochemical group contain at least about 40% fluorine by weight, more preferably at least about 50% fluorine by weight. The terminal portion of the group is generally fully-fluorinated, preferably containing at least 7 fluorine atoms, e.g., CF3CF2CF2xe2x80x94, (CF3)2CFxe2x80x94, SF5CF2xe2x80x94. Perfluorinated aliphatic groups (i.e., those of the formula CnF2n+1xe2x80x94) are the most preferred fluorochemical groups.
Representative examples of suitable fluorochemicals include fluorochemical urethanes, ureas and substituted ureas, esters, ethers, alcohols, epoxides, allophanates, amides, amines (and salts thereof), acids (and salts thereof), carbodiimides, guanidines, oxazolidinones, isocyanurates, piperazines, aminoalcohols, sulfones, imides, biurets, acrylate and methacrylate homopolymers and copolymers, siloxanes, alkoxysilanes, chlorosilanes, and mixtures thereof.
Representative fluorochemical group-containing polymers useful in the present invention include fluorochemical acrylate and methacrylate homopolymers or copolymers containing fluorochemical acrylate monomers interpolymerized with monomers such as methyl methacrylate, butyl acrylate, octadecylmethacrylate, acryl ate and meth acryl ate esters of oxyalkylene and polyoxyalkylene polyol oligomers (e.g., oxyethylene glycol dimethacrylate, polyoxyethylene glycol dimethacrylate, methoxy acrylate, and polyoxyethylene acrylate), glycidyl methacrylate, ethylene, butadiene, styrene, isoprene, chloroprene, vinyl acetate, vinyl chloride, vinylidene chloride, vinylidene fluoride, acrylonitrile, vinyl chloroacetate, vinylpyridine, vinyl alkyl ethers, vinyl alkyl ketones, acrylic acid, methacrylic acid, 2-hydroxyethylacrylate, N-methylolacrylamide, 2-(N,N,N-trimethylammonium)ethyl methacrylate, and 2-acrylamido-2-methylpropanesulfonic acid (AMPS). The relative amounts of various comonomers used can generally be selected empirically, depending on the substrate to be treated, the properties desired, and the mode of application to the substrate. Useful fluorochemicals also include blends of the various fluorochemicals described above.
Also useful in the present invention are blends of fluorochemicals with fluorine-free extender compounds, such as siloxanes, (meth)acrylate and substituted acrylate polymers and copolymers, N-methylolacrylamide-containing acrylate polymers, urethanes, blocked isocyanate-containing polymers and oligomers, condensates or precondensates of urea or melamine with formaldehyde, glyoxal resins, condensates of fatty acids with melamine or urea derivatives, condensates of fatty acids with polyamides and their epichlorohydrin adducts, waxes, polyethylene, chlorinated polyethylene, alkyl ketene dimers, esters, and amides. Blends of these fluorine-free extender compounds can also be used. The relative amount of extender compound to fluorochemical is not critical. However, the overall composition of the fluorochemical treatment generally contains, relative to the amount of solids present in the system, at least about 3 weight percent, preferably at least about 5 weight percent, carbon-bound fluorine in the form of said fluorochemical groups.
Many fluorochemicals, including blends that include fluorine-free extender molecules such as those described above, are commercially available as ready-made formulations. Such products are sold, for example, as Scotchgard(trademark) brand Carpet Protector (manufactured by 3M Co., Saint Paul, Minn.) and as Zonyl(trademark) brand Carpet Treatment (manufactured by E.I. du Pont de Nemours and Company, Wilmington, Del.).
Useful fluorochemicals are described in European Patent No. 0 613 462 (Minnesota Mining and Manufacturing Company) and in U.S. Pat. No. 3,728,151 (Sherman et al.), U.S. Pat. No. 3,816,229 (Bierbrauer), U.S. Pat. No. 3,896,035 (Schultz et al.), U.S. Pat. No. 3,901,727 (Loudas), U.S. Pat. No. 3,916,053 (Sherman et al.), U.S. Pat. No. 4,043,923 (Loudas), U.S. Pat. No. 4,043,964 (Sherman et al.), U.S. Pat. No. 4,264,484 (Patel), U.S. Pat. No. 4,624,889 (Bries), U.S. Pat. No. 5,274,159 (Pellerite et al.), U.S. Pat. No. 5,380,778 (Buckanin), and U.S. Pat. No. 5,451,622 (Boardman et al.), the descriptions of which are incorporated herein by reference.
Fluorochemical repellents suitable for use as polymer melt additives are preferably stable at temperatures of 250xc2x0 C. and above (more preferably, 300xc2x0 C. and above), are preferably miscible with the insulating material at the melt processing temperature, and are preferably capable of migration to the surface of the insulating material. Thus, a preferred class of fluorochemical repellents, useful both in topical treatments and as polymer melt (or other bulk polymer) additives, includes fluorochemical oxazolidinone compositions or fluorochemical oxazolidinones comprising normally solid, water-insoluble, fluoroaliphatic radical-containing 2-oxazolidinone compounds, the compounds comprising one or more 2-oxazolidinone moieties, 
at least one of which has a monovalent fluoroaliphatic radical, Rf, bonded to the 5-position carbon atom thereof by an organic linking group.
A preferred subclass of such fluoroaliphatic radical-containing oxazolidinone compounds is that represented by Formula II below: 
where each R1 is independently hydrogen or an organic radical, which organic radical can contain xe2x80x94Qxe2x80x94Rf where Q is a linking group and Rf is a fluoroaliphatic radical that can optionally contain one or more catenary (in-chain) heteroatoms such as oxygen; each R2 is independently an organic radical, which organic radical can contain xe2x80x94Qxe2x80x94Rf where Q and Rf are as defined above; with the proviso that there is at least one Rf radical in one of R1 and R2; each A is independently an organic radical; a is zero or 1; b is a number from 0 to about 6; c is 0, 1, or 2; and the sum of a+b+c is at least 1. Preferably, R1 is an organic radical that contains xe2x80x94QRf, where Rf is a perfluoroalkyl group having from about 3 to about 20 carbon atoms (preferably, from about 4 to about 12 carbon atoms), and Q comprises a heteroatom-containing group, an organic group, or a combination thereof (preferably, Q is xe2x80x94SO2N(Rxe2x80x2)(CH2)kxe2x80x94, xe2x80x94(CH2)kxe2x80x94, xe2x80x94CON(Rxe2x80x2)(CH2)kxe2x80x94, or xe2x80x94(CH2)kSO2N(Rxe2x80x2)(CH2)kxe2x80x94, where Rxe2x80x2 is hydrogen, phenyl, or a short chain (up to about 6 carbon atoms) alkyl group (preferably, methyl or ethyl), and each k is independently an integer from 1 to about 20); a is 1; b is 0; c is 0; and A is an alkyl group having from about 12 to about 22 carbon atoms. Formula II represents individual compounds or mixtures of compounds, for example, as they are obtained as products from reactions used in their preparation.
Such fluorochemical oxazolidinone compositions can be prepared using known organic reactions, for example, by the reaction of epoxides or halohydrins (for example, chlorohydrins or bromohydrins) with organic isocyanates in each which reaction at least one of the reactants contains an Rf radical. The reactions can be carried out stepwise by reacting the halohydrin with the isocyanate under urethane bond-forming conditions, for example, 20xc2x0 C. to 100xc2x0 C. for about 1 to 24 hours, to form a urethane intermediate, followed by addition of a base and reaction at about 20xc2x0 C. to 100xc2x0 C. for about 1 to 24 hours to form the oxazolidinone composition. Alternatively, an epoxide can be reacted with an isocyanate in the presence of a catalyst, such as diethyl zinc, to form the oxazolidinone directly.
Suitable fluorochemical oxazolidinones and methods for their preparation are further described in U.S. Pat. Nos. 5,025,052 and 5,099,026 (Crater et al.), the descriptions of which are incorporated herein by reference.
Other preferred fluorochemical repellents, useful both in topical treatments and as polymer melt (or other bulk polymer) additives, include those described in U.S. Pat. No. 3,899,563 (Oxenrider et al.), U.S. Pat. No. 4,219,625 (Mares et al.), U.S. Pat. No. 5,560,992 (Sargent et al.), and U.S. Pat. No. 5,681,963 (Liss); International Patent Publication Nos. WO 97/22576, WO 97/22659, and WO 97/22660 (E. I. du Pont de Nemours and Company); Japanese Patent Publication Nos. 3-041160 (Kao Corporation) and 9-323956 (Wako Junyaku Kogyo Co.); and International Patent Publication No. WO 99/05345 (Minnesota Mining and Manufacturing Company), the descriptions of which are incorporated herein by reference.
Of these, particularly preferred are the fluorochemical group-containing derivatives of long-chain (preferably, having at least about 30 carbon atoms; more preferably, dimer and trimer, as defined below) acids, alcohols, and amines. A preferred class of such derivatives includes the compounds or mixtures of compounds represented by the formulas:
{(Rf)nxe2x80x94Qxe2x80x94Oxe2x80x94C(O)}pxe2x80x94A
{(Rf)nxe2x80x94Qxe2x80x94C(O)xe2x80x94O}pxe2x80x94Axe2x80x2
xe2x80x83{(Rf)nxe2x80x94Qxe2x80x94N(R)xe2x80x94C(O)}pxe2x80x94A
{(Rf)nxe2x80x94Qxe2x80x94C(O)xe2x80x94N(R)}pxe2x80x94Axe2x80x2
wherein Rf is a fluorinated alkyl group (which can optionally contain one or more catenary (in-chain) heteroatoms such as oxygen) bonded through carbon; n is 1 or 2; Q is a divalent or trivalent linking group or a covalent bond; p is 2 or more, up to the valency of A or Axe2x80x2; R is a hydrogen atom or is a substituted or unsubstituted alkyl group; A is the residue of a dimer or trimer acid; and Axe2x80x2 is the residue of a dimer diol, a dimer diamine, a trimer triol, or a trimer triamine. Preferably, Rf is a perfluoroalkyl group having from about 3 to about 20 carbon atoms (preferably, from about 4 to about 12 carbon atoms); R is an alkyl group having from 1 to 6 carbon atoms; Q is xe2x80x94SO2N(Rxe2x80x2)(CH2)kxe2x80x94, xe2x80x94(CH2)kxe2x80x94, xe2x80x94CON(Rxe2x80x2)(CH2)kxe2x80x94, or xe2x80x94(CH2)kSO2N(Rxe2x80x2)(CH2)kxe2x80x94, where Rxe2x80x2 is hydrogen, phenyl, or a short chain (up to about 6 carbon atoms) alkyl group (preferably, methyl or ethyl), and each k is independently an integer from 1 to about 20; A is the residue of a dimer acid; and Axe2x80x2 is the residue of a dimer diol or dimer diamine. The esters and xe2x80x9creversexe2x80x9d esters are preferred over the amides and xe2x80x9creversexe2x80x9d amides.
Such fluorochemical group-containing dimer and trimer acid esters can be prepared by heating a fluorochemical alcohol with either a dimer acid or a trimer acid in the presence of a standard acid catalyst, or by first making an acid chloride of the dimer/trimer acid and then reacting the acid chloride with a fluorochemical alcohol at a slightly elevated temperature (for example, 50-60xc2x0 C.) in the presence of an acid scavenger. Fluorochemical group-containing xe2x80x9creversexe2x80x9d esters can be prepared by reacting a fluorochemical carboxylic acid with a dimer diol, using the same synthetic procedure as described for preparing esters. Fluorochemical group-containing amides can be prepared by reacting a fluorochemical amine with a dimer or trimer acid by heating the components together neat at an elevated temperature (at least about 220xc2x0 C.), or by first making an acid chloride of the dimer/trimer acid and then reacting the acid chloride with a fluorochemical amine at a slightly elevated temperature. Fluorochemical group-containing xe2x80x9creversexe2x80x9d amides can be prepared by reacting a fluorochemical carboxylic acid with a dimer amine, using the same synthetic procedure as described for preparing esters.
The terms xe2x80x9cdimer acidxe2x80x9d and xe2x80x9ctrimer acidxe2x80x9d refer to oligomerized unsaturated fatty acid products of relatively high molecular weight. The products are mixtures comprising various ratios of a variety of large or relatively high molecular weight substituted cyclohexenecarboxylic acids, predominately 36-carbon dibasic acids (dimer acid) and 54-carbon tribasic acids (trimer acid), with no single structure sufficient to characterize each. Component structures can be acyclic, cyclic (monocyclic or bicyclic), or aromatic.
Dimer and trimer acids (for use in preparing the above-described fluorochemical repellents) can be prepared by condensing unsaturated monofunctional carboxylic acids such as oleic, linoleic, soya, or tall oil acid through their olefinically unsaturated groups, in the presence of catalysts such as acidic clays. Dimer/trimer acids are commercially available from a variety of vendors, including Henkel Corporation/Emery Group (as Empol(trademark) 1008, 1061, 1040 and 1043) and Unichema North America (as Pripol(trademark) 1004 and 1009). Dimer diols and diamines can be made from the corresponding dimer acid by methods well known in the art. Dimer diols are commercially available from Henkel Corp./Emery Group as Empol(trademark) 1070 and 1075 diols. Dimer amines are commercially available from Witco Corp., for example, as Kemamine(trademark) DP-3695 amine.
Insulating Materials
Insulating materials that are suitable for topical treatment include materials that have relatively low surface and bulk conductivity and that are prone to static charge buildup. Such materials include both synthetic and naturally-occurring polymers (or the reactive precursors thereof, for example, mono- or multifunctional monomers or oligomers) that can be either organic or inorganic in nature, as well as ceramics, glasses, and ceramic/polymer composites or ceramers (or the reactive precursors thereof).
Suitable synthetic polymers (which can be either thermoplastic or thermoset) include commodity plastics such as, for example, poly(vinyl chloride), polyethylenes (high density, low density, very low density), polypropylene, and polystyrene; engineering plastics such as, for example, polyesters (including, for example, poly(ethylene terephthalate) and poly(butylene terephthalate)), polyamides (aliphatic, amorphous, aromatic), polycarbonates (for example, aromatic polycarbonates such as those derived from bisphenol A), polyoxymethylenes, polyacrylates and polymethacrylates (for example, poly(methyl methacrylate)), some modified polystyrenes (for example, styrene-acrylonitrile (SAN) and acrylonitrile-butadiene-styrene (ABS) copolymers), high-impact polystyrenes (SB), fluoroplastics, and blends such as poly(phenylene oxide)-polystyrene and polycarbonate-ABS; high-performance plastics such as, for example, liquid crystalline polymers (LCPs), polyetherketone (PEEK), polysulfones, polyimides, and polyetherimides; thermosets such as, for example, alkyd resins, phenolic resins, amino resins (for example, melamine and urea resins), epoxy resins, unsaturated polyesters (including so-called vinyl esters), polyurethanes, allylics (for example, polymers derived from allyldiglycolcarbonate), fluoroelastomers, and polyacrylates; and the like and blends thereof. Suitable naturally occurring polymers include proteinaceous materials such as silk, wool, and leather; and cellulosic materials.
Thermoplastic and thermoset polymers, including those described above, are preferred insulating materials, as such polymers can either be topically treated with the antistat/repellent combination or can be combined with it (in bulk) to form a blend. Thermoplastic polymers are more preferred in view of their melt processability. Preferably, the thermoplastic polymers are melt processable at elevated temperatures, for example, above about 150xc2x0 C. (more preferably, above about 250xc2x0 C.; even more preferably, above about 280xc2x0 C.; most preferably, above about 320xc2x0 C.). Preferred thermoset polymers include polyurethanes, epoxy resins, and unsaturated polyesters. Preferred thermoplastic polymers include, for example, polypropylene, polyethylene, copolymers of ethylene and one or more alpha-olefins (for example, poly(ethylene-butene) and poly(ethylene-octene)), polyesters, polyurethanes, polycarbonates, polyetherimides, polyimides, polyetherketones, polysulfones, polystyrenes, ABS copolymers, polyamides, fluoroelastomers, and blends thereof. More preferred are polypropylene, polyethylene, polyesters, poly(ethylene-octene), polyurethanes, polycarbonates, and blends thereof, with polypropylene, polyethylene, poly(ethylene-octene), polyurethanes, and blends thereof being most preferred.
Preparation and Use of Composition
Preferably, the composition of the invention can be prepared by (a) combining at least one ionic salt antistat, at least one fluorochemical repellent, and at least one thermoplastic polymer (optionally, along with other additives) and then melt processing the resulting combination; or (b) combining at least one ionic salt antistat, at least one fluorochemical repellent, and at least one thermosetting polymer or ceramer or the reactive precursors thereof (optionally, along with other additives) and then allowing the resulting combination to cure, optionally with the application of heat or actinic radiation. Alternative processes for preparing the composition include, for example, (c) applying a treatment composition comprising at least one ionic salt antistat and at least one fluorochemical repellent to at least a portion of at least one surface of at least one insulating material; (d) dissolving at least one ionic salt antistat, at least one fluorochemical repellent, and at least one insulating material in at least one solvent and then casting or coating the resulting solution and allowing evaporation of the solvent, optionally with the application of heat; and (e) combining at least one ionic salt antistat, at least one fluorochemical repellent, and at least one monomer (optionally, along with other additives) and then allowing polymerization of the monomer to occur, optionally in the presence of at least one solvent and optionally with the application of heat or actinic radiation. If desired, the antistat and repellent can be utilized separately, for example, one can be added prior to melt processing, and the other can then be topically applied to the resulting melt-processed combination. Separate topical treatments, etc., are also possible.
To form a melt blend by melt processing, the ionic salt antistat(s) and fluorochemical repellent(s) can be, for example, intimately mixed with pelletized or powdered polymer and then melt processed by known methods such as, for example, molding, melt blowing, melt spinning, or melt extrusion. The antistat and repellent additives can be mixed directly with the polymer or they can be mixed with the polymer in the form of a xe2x80x9cmaster batchxe2x80x9d (concentrate) of the additives in the polymer. If desired, an organic solution of the additives can be mixed with powdered or pelletized polymer, followed by drying (to remove solvent) and then by melt processing. Alternatively, the additives can be injected into a molten polymer stream to form a blend immediately prior to, for example, extrusion into fibers or films or molding into articles.
After melt processing, an annealing step can be carried out to enhance the development of antistatic and repellent characteristics. In addition to, or in lieu of, such an annealing step, the melt processed combination (for example, in the form of a film or a fiber) can also be embossed between two heated rolls, one or both of which can be patterned. An annealing step typically is conducted below the melt temperature of the polymer (for example, in the case of polyamide, at about 150-220xc2x0 C. for a period of about 30 seconds to about 5 minutes). In some cases, the presence of moisture can improve the effectiveness of the ionic salt antistat(s), although the presence of moisture is not necessary in order for antistatic characteristics to be obtained.
The ionic salt antistat(s) and fluorochemical repellent(s) can be added to thermoplastic or thermosetting polymer (or, alternatively, to other insulating material) in amounts sufficient to achieve the desired antistatic and repellency properties for a particular application. The amounts can be determined empirically and can be adjusted as necessary or desired to achieve the antistatic and repellency properties without compromising the properties of the polymer (or other insulating material). Generally, the ionic salt antistat(s) and the fluorochemical repellent(s) can each be added in amounts ranging from about 0.1 to about 10 percent by weight (preferably, from about 0.5 to about 2 percent; more preferably, from about 0.75 to about 1.5 percent) based on the weight of polymer (or other insulating material).
In topical treatment of an insulating material, the combination of ionic salt antistat(s) and fluorochemical repellent(s) can be employed alone or in the form of aqueous suspensions, emulsions, or solutions, or as organic solvent (or organic solvent/water) solutions, suspensions, or emulsions. Useful organic solvents include chlorinated hydrocarbons, alcohols (for example, isopropyl alcohol), esters, ketones (for example, methyl isobutyl ketone), and mixtures thereof. Generally, the solvent solutions can contain from about 0.1 to about 50 percent, or even up to about 90 percent, by weight non-volatile solids (based on the total weight of the components). Aqueous suspensions, emulsions, or solutions are generally preferred and generally can contain a non-volatile solids content of about 0.1 to about 50 percent, preferably, about 1 to about 10 percent, by weight (based on the total weight of the components). Alternatively, however, topical treatment can be carried out by applying (to at least a portion of at least one surface of at least one insulating material) a topical treatment composition that comprises at least one ionic salt antistat that is liquid at the use or treatment temperature. Such a topical treatment process can involve the use of the neat liquid ionic salt antistat, without added solvent, and is thus preferred from an environmental perspective over the use of organic solvent solutions of the antistat/repellent combination.
The topical treatment compositions comprising the antistat/repellent combination can be applied to an insulating material by standard methods such as, for example, spraying, padding, dipping, roll coating, brushing, or exhaustion (optionally followed by the drying of the treated material to remove any remaining water or solvent). The material can be in the form of molded or blown articles, sheets, fibers (as such or in aggregated form, for example, yarn, toe, web, or roving, or in the form of fabricated textiles such as carpets), woven and nonwoven fabrics, films, etc. If desired, the antistat/repellent combination can be co-applied with conventional fiber treating agents, for example, spin finishes or fiber lubricants.
The topical treatment compositions can be applied in an amount sufficient to achieve the desired antistatic and repellency properties for a particular application. This amount can be determined empirically and can be adjusted as necessary or desired to achieve the antistatic and repellency properties without compromising the properties of the insulating material.
Any of a wide variety of constructions can be made from the composition of the invention, and such constructions will find utility in any application where some level of antistatic and repellency characteristics is required. For example, the composition of the invention can be used to prepare films and molded or blown articles, as well as fibers (for example, melt-blown or melt-spun fibers, including microfibers) that can be used to make woven and nonwoven fabrics. Such films, molded or blown articles, fibers, and fabrics exhibit antistatic and water and oil repellency (and soil resistance) characteristics under a variety of environmental conditions and can be used in a variety of applications.
For example, molded articles comprising the composition of the invention can be prepared by standard methods (for example, by high temperature injection molding) and are particularly useful as, for example, headlamp covers for automobiles, lenses (including eyeglass lenses), casings or circuit boards for electronic devices (for example, computers), screens for display devices, windows (for example, aircraft windows), and the like. Films comprising the composition of the invention can be made by any of the film making methods commonly employed in the art. Such films can be nonporous or porous (the latter including films that are mechanically perforated), with the presence and degree of porosity being selected according to the desired performance characteristics. The films can be used as, for example, photographic films, transparency films for use with overhead projectors, tape backings, substrates for coating, and the like.
Fibers comprising the composition of the invention can be used to make woven or nonwoven fabrics that can be used, for example, in making medical fabrics, medical and industrial apparel, fabrics for use in making clothing, home furnishings such as rugs or carpets, and filter media such as chemical process filters or respirators. Nonwoven webs or fabrics can be prepared by processes used in the manufacture of either melt-blown or spunbonded webs. For example, a process similar to that described by Wente in xe2x80x9cSuperfine Thermoplastic Fibers,xe2x80x9d Indus. Eng""g Chem. 48, 1342 (1956) or by Wente et al. in xe2x80x9cManufacture of Superfine Organic Fibers,xe2x80x9d Naval Research Laboratories Report No. 4364 (1954) can be used. Multi-layer constructions made from nonwoven fabrics enjoy wide industrial and commercial utility, for example, as medical fabrics. The makeup of the constituent layers of such multi-layer constructions can be varied according to the desired end-use characteristics, and the constructions can comprise two or more layers of melt-blown and spunbonded webs in many useful combinations such as those described in U.S. Pat. No. 5,145,727 (Potts et al.) and U.S. Pat. No. 5,149,576 (Potts et al.), the descriptions of which are incorporated herein by reference. In multi-layer constructions, the ionic salt antistat(s) and fluorochemical repellent(s) can be used in combination in one or more layers, or each can be independently segregated in one or more layers. For example, in a spunbonded/melt-blown/spunbonded (xe2x80x9cSMSxe2x80x9d) three-layer construction, the ionic salt antistat(s) can be used in one or both spunbonded layers, and the fluorochemical repellent(s) can be used in the melt-blown layer, to impart both antistatic and repellency characteristics to the overall construction.
The ionic salt antistat(s) and fluorochemical repellent(s) used in the composition of the invention can also find utility as additives to coatings (for example, polymer or ceramer coatings). Such coatings can be antistatic, water- and oil-repellent, and scratch-resistant (as well as soil-resistant) and can be used in the photographic industry or as protective coatings for optical or magnetic recording media.
If desired, the composition of the invention can further contain one or more conventional additives commonly used in the art, for example, dyes, pigments, antioxidants, ultraviolet stabilizers, flame retardants, surfactants, plasticizers, tackifiers, fillers, and mixtures thereof. In particular, performance enhancers (for example, polymers such as polybutylene) can be utilized to improve the antistatic and/or repellency characteristics in, for example, melt additive polyolefin applications.
Objects and advantages of this invention are further illustrated by the following examples, but the particular materials and amounts thereof recited in these examples, as well as other conditions and details, should not be construed to unduly limit this invention. In the examples, where weight percent or parts by weight are indicated, these are based on the weight of the entire composition unless indicated otherwise.